One of the most-watched private-equity partnerships in Silicon Valley is coming apart.

Marc Bodnick, a cofounder of Elevation Partners, is planning to leave, according to a source close to the firm.

His departure could threaten Elevation’s plans to raise a second fund, which have been on hold as the firm has struggled to convince investors it can recapture its early magic.

Elevation Partners, formed in 2003, brought together a literal rock star — Bono of U2 — with some of the Valley’s savviest investors, including Bodnick and Roger McNamee, who had previously worked together at Silverlake Capital; former EA executive John Riccitiello; and ex-Apple CFO Fred Anderson.

In a San Jose Mercury News profile of Elevation Partners, Bodnick got most of the credit for turning around the fortunes of the firm’s first fund, largely through investments he led in Yelp, the local-reviews website, and Facebook, the world’s largest social network (where, it’s worth noting, Bodnick’s sister-in-law, Sheryl Sandberg, is chief operating officer).

Elevation invested in Facebook shares at a $13 billion valuation; the company was recently valued at $50 billion by DST and Goldman Sachs when they bought $1.5 billion in Facebook shares from the company and other investors.

Bodnick also led Elevation’s $100 million investment in Yelp, where he currently serves as a member of the board. A Yelp spokesman could not immediately say if the company had plans to replace Bodnick on the board.

Those are two bright spots in an otherwise troubled record. The firm’s high-profile investment in Palm looked messy as its big bet on new smartphones failed to pan out, although Elevation ended up making a modest profit when the smartphone maker was sold to HP last year. That was largely thanks to favorably priced warrants Elevation had negotiated at the time it invested.

After the Palm deal closed, Elevation lost Patty Halfen Wexler, a well-regarded principal at the firm, and let other staffers go.

Around the same time, Elevation hired former eBay CFO Rajiv Dutta and former Apple executive Avie Tevanian as managing directors, suggesting ambitious plans for new investments.